1. Field of the Invention
The present invention relates to a cutting method and a method of manufacturing a semiconductor device, capable of effectively removing burrs.
2. Description of the Related Art
In semiconductor device manufacturing steps, steps are performed such as a cutting step of separating each partitioned region (chip: “semiconductor device”), in which a given circuit pattern is formed on a semiconductor wafer (“group of semiconductor devices”), using a cutting device called dicer or dicing, (See Japanese Patent Application Laid-open Publication No. 2001-77055), and a cutting step of separating each partitioned region (package: “semiconductor device”) from a leadframe (“group of semiconductor devices”) in plate form to which chips are mounted and wire-bonded and that is sealed by a sealing agent having an insulating property.
Here, the semiconductor wafer cutting step is performed by moving the semiconductor wafer in a direction along a cutting line for cutting by an annular cutting blade that is driven to rotate. It is to be noted that, in silicon wafers, a metal wiring layer (“first layer”), made of a ductile metal such as aluminum or copper, is stacked on top of a silicon substrate (“second layer”) that exhibits hard and brittle properties, and the metal wiring layer and the silicon substrate stacked at each boundary between chips are cut in the cutting step.
On the other hand, the leadframe cutting step is carried out similarly by moving the leadframe in a direction along a cutting line for cutting by an annular cutting blade that is driven to rotate. It is to be noted that, at least on the side surface of each of the packages in a leadframe after sealing, a hard and brittle sealing agent layer (“second layer”) such as thermosetting resin or thermoplastic resin is stacked on top of electrodes (“first layer”), made of copper, aluminum or iron-nickel alloy, on the mounting surface side, and the electrodes and the sealing agent layer stacked at each boundary between chips are cut in the cutting step.
While a soft and ductile metal material such as copper or aluminum is cut in the aforementioned cutting steps, it is known that cutting such a metal material produces burrs (excess material, debris) on the cut cross-sections.
In this case it is possible that electrodes (bonding pads) arranged at the perimeter portion of the chip front surface or electrodes (external terminals) arranged at the perimeter portion of the package mounting surface could be short-circuited via the produced burrs, thus resulting in increased manufacturing defects of semiconductor devices.
Further, fine pitch techniques are increasingly used as a result of recent trends toward downsizing and thickness reduction of semiconductor devices, possibly resulting in aggravating the aforementioned problem if burrs are produced between reduced pitch spacings.